This afternoon Sarepta Therapeutics, Inc. announced that the FDA has placed a clinical hold on SRP-5051 (vesleteplirsen) following a serious adverse event of hypomagnesemia (low magnesium). SRP-5051 is Sarepta’s next-generation peptide-conjugated phosphorodiamidate morpholino oligomer (PPMO) to treat patients with Duchenne muscular dystrophy who are amenable to exon 51 skipping. 

This hold means that dosing is paused and new patients may not be enrolled in Study SRP-5051-201 (MOMENTUM) in the United States until the hold is lifted. 

The FDA has requested information on all cases of hypomagnesemia in the trial so that they can review Sarepta’s risk and safety monitoring plans.  This side effect of hypomagnesemia has been seen in other patients on SRP-5051, but past cases were milder. According to the community letter (below), Sarepta will respond to the agency with this information, including proposed changes to the monitoring plan in the next few days. 

We appreciate that Sarepta will work to share information with FDA with the goal of resuming screening and dosing in the U.S. as quickly as possible, keeping the safety of all patients as top priority. Sarepta will present an update on SRP-5051 to the community during the Restoring Dystrophin via Exon Skipping Strategies panel on Friday, June 24th during PPMD’s 2022 Annual Conference. 

For more information about this clinical hold, please read the Community Letter here.